As is commonly known, when an uppermost one of multiple sheet materials stacked in a stocker is taken out sequentially, there is a request to prevent that two sheet materials are taken out simultaneously (i.e. double take-out of sheet materials). For example, a patent document 1 discloses a sheet material transfer device including a tool for preventing double take-out of sheet materials.
According to a technique described in patent document 1, a tool for preventing double take-out of sheet materials is provided which includes a hole slightly smaller than target sheets, and when a sheet is taken out from a stocker by a sheet take-out means, edge parts of the sheet is bent downwardly by passing the sheet through the tool. According to this method, it is said that the sheet materials can be reliably taken out one by one by leaving the uppermost sheet only and separating the other sheets by the sheet take-out means when two or more of the target sheet materials are stacked.
However, even if the technique described in patent document 1 can be applied to a flexible sheet such as paper or cloth, there is room for improvement because it is difficult to pass the sheet through the tool for preventing double take-out in a case of a relatively high rigidity sheet such as a resin sheet.